Engineering Calculation Pipeline

(1)

(2)

REVISION RECORD:

Revision

No.

Reason for revision

Date

0 Issued for Construction

19.12.2012

C

Re-Issued for Approval incorporating Client comments

09.12.2012

B

Issued for Approval incorporating Client comments

06.11.2012

A

Issued for Client Review

16.10.2012

(3)

1. INTRODUCTION ...

₅

1.1. Background ...

5

1.2. Project Description ...

5

2. DEFINITIONS ...

₅

3. SCOPE ...

₆

4. REFERENCE CODES, STANDARDS AND SPECIFICATIONS ...

₆

4.1. General ...

6

4.2. International Codes and Standards ...

6

4.3. Project Documents ...

6

5. PIPELINE DESIGN DATA ...

₇

6. DESCRIPTION / METHODOLOGY - WALL THICKNESS CALCULATION...

₈

6.1. General ...

8

6.2. Pipe Thickness Check for Stress Value ...

9

6.3. Minimum Elastic Bending Radius ...

11

6.4. Bend Thinning Requirements ...

11

7. DESCRIPTION / METHODOLOGY - UPHEAVAL BUCKLING CALCULATION

₁₂

7.1. General ...

12

7.2. Methodology ...

12

7.3. Calculation for Axial Force (P) ...

12

7.4. Imperfection Length ...

13

8. DESCRIPTION / METHODOLOGY – ROAD CROSSING CALCULATION ...

14

8.1. General ...

14

8.2. Methodology ...

14

9. CALCULATION RESULT / SUMMARY ...

₁₇

9.1. Result for Wall Thickness Calculation ...

17

9.2. Result for Upheaval Buckling Calculation ...

21

9.3. Result for Crossing Calculation ...

22

9.4. Result for Anchor Load, Active length, free end expansion and Buoyancy

23 Corroded Condition...

24 ATTACHMENT-1A & 1B: WALL THICKNESS CALCULATIONS (CORRODED & NEW CONDITION)

...

₂₆

ATTACHMENT-2: UPHEAVAL BUCKLING CALCULATION ...

₂₇

(4)

ATTACHMENT-4: PIPELINE BUOYANCY CALCULATION ...

₂₉

ATTACHMENT-5: ANCHOR LOAD, ACTIVE LENGTH & FREE EXPANSION CALCULATION 30

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1. INTRODUCTION

1.1. Background

Abu Dhabi Gas Industries Limited (GASCO) intends to supply sales gas to Emirates Aluminium

(EMAL) for their second expansion requirements, to MASDAR for their new Carbon Capture &

Storage Project Requirements and other new consumers identified by ADNOC as part of their

next five year gas supply plan in Taweelah Area.

DODSAL ENGINEERING & CONSTRUCTION PTE LIMITED is EPC Contractor for the project of

Habshan – Maqta -Taweelah Gas Pipelines Project abbreviated to HMT Gas Pipelines Project.

The Owner Company for this project is Abu Dhabi Gas Industries Ltd. (GASCO).

1.2. Project Description



Two (2) Nos. new 52” pipelines from Habshan to Maqta premises (approx. 125 km.each) with

Scraper Launcher, Scraper Receiver and intermediate Block Valve Stations.



One (1) No. new 52” pipeline from Maqta to Taweelah KM42 point (approx. 42 km.) with

Scraper Launcher, Scraper Receiver and intermediate Block Valve Stations.



One (1) No. new 42” pipeline from Taweelah KM42 point to ADWEC CRS (approx. 11 km.)

with Scraper Launcher and Receiver Stations. Scraper receiver station at ADWEC CRS shall

include ROV, FCV, Filters, Metering skid and PRS for custody transfer to Khalifa Port

(KIZAD). Scraper Receiver station shall also include plot area provision for future filters,

Custody Transfer/Metering and PRS for ADWEC (Taweelah) and MASDAR (with ADWEC).



Supervisory and Monitoring Systems for the new pipelines and upgrading of the existing SMC

system to include new facilities.



Associated Civil, Electrical, Instrumentation, Telecom and Cathodic Protection works



Demolition of existing 30” pipeline from Bab to Maqta manifold.



Demolition of existing 24” pipeline from Maqta to Taweelah Consumer Receipt Station.

2. DEFINITIONS

In this document following words and expressions shall have the meanings hereby assigned to

them except where the content otherwise requires:

COMPANY

: Abu Dhabi Gas Industries Ltd. (GASCO)

CONTRACTOR

: Dodsal Engineering & Construction Pte. Ltd.

(6)

3. SCOPE

This document covers the Calculations for Pipeline Wall Thickness, Upheaval buckling,

Buoyancy, Crossing, Anchor load, Active length and Free expansion for

“Habshan-Maqta-Taweelah (HMT) Gas Pipelines Project”. The thickness will be verified as per ASME B31.8 for gas

pipelines.

4. REFERENCE CODES, STANDARDS AND SPECIFICATIONS

4.1. General

These pipeline calculations were performed in conformance with the current issue, amendments

and Project Addendum of the following codes, standards and specifications prevailing on the

effective date of the contract.

4.2. International Codes and Standards

The following codes and standards form the basis for the pipelines calculations.

ASME B 31.8 Ed 2010

Gas Transmissions and Distribution Piping Systems

PD 8010-1:2004

Code of Practice for Pipelines Part 1 - Steel Pipelines on Land

API 5L 44

th

Edition

Specification for Line Pipe

API RP 1102 7

th

Edition

Steel Pipeline Crossing Rail, Roads and Highways

4.3. Project Documents

5272-PP-GEN-00-001

Process Design Basis.

5272-RT-GEN-95-001

Pipeline Design Basis

5272-ADD-9550-004

Addendum to DGS Flexibility analysis (Pipeline)

5272-ADD-9550-003

Addendum to DGS for Pipeline Hydrostatic Testing

5272-ADD-9550-002

Addendum to DGS Pipeline Construction

(7)

5. PIPELINE DESIGN DATA

Parameters

Thammama C - Maqta

Maqta – KM 42

KM 42 –

Taweelah

SV2 to

Yas

island

tie-in

Pipeline diameter. NB

52

42

16 Outside Diameter mm

1320.8

1066.8

406.4 Design Code, ASME

B31.8

Design Pressure, bar

(g)

63.5

63.5 Corrosion Allowance,

mm

1.5

1.5 Maximum Design

Temp. Above Ground

(ºC)

100

100 Maximum Design

Temp. Below Ground

(ºC)

65

65 Warmest or Coldest

Operating Temp. (ºC)

65

65 Minimum Design

Temp. of pipeline

system (ºC)

0 (Note 1)

0 (Note 1) 0 (Note1)

Max. Temp. at 1m

depth of soil (ºC)

38

38 Minimum Tie-in Temp.,

underground section

(ºC)

13

13 Minimum Tie-in Temp.,

aboveground section

(ºC)

5

5 Flange Rating, ASME

Class

600

600 Min burial depth to top

of pipe (normal terrain),

m

1

1 Material Grade, API 5L

X 65MS, PSL 2

X 65MS,

PSL 2

X 65MS,

PSL 2

Material SMYS, MPa

450

450 Design Factor, F

CLASS 1

CLASS

3 CLASS

(8)

Parameters

Thammama C - Maqta

Maqta – KM 42

KM 42 –

Taweelah

SV2 to

Yas

island

tie-in

Mainline

0.72

0.5

0.4

0.5

0.4

0.5

0.5 Track/Asphalt

Road/Rig Crossings

0.5

0.4

0.5

0.4

0.5

0.5 Stations (SVs &

Launcher/receivers)

0.5

0.4

0.5

0.4

0.5

0.5 Co-efficient of Thermal

Expansion, mm/deg C

11.7 x 10

-6

_{11.7 x 10}

-6

_{11.7 x 10}

-6

_{11.7 x 10}

-6

Elastic Modulus E, Mpa

207.0 x 10³

207.0 x

10³

207.0 x

10³

Internal coating

thickness

60 – 100 microns

60 – 100

microns

Not

applicable

External Coating

3 Layer Polyethylene

3 Layer

Polyethylen

e

3 Layer

Polyethylen

e

Minimum External

Coating Thickness, mm

(FBE+Adhesive+PE)

3.55

3.05 Note 1: Min. Design temperature is confirmed as per depressurization study.

6. DESCRIPTION / METHODOLOGY - WALL THICKNESS CALCULATION

6.1. General

Pipelines wall thickness is calculated based on the internal design pressure and in accordance

with the Design codes for gas pipelines as described below. Calculations are done for location

class 1, 3 and 4 of gas pipeline with design factors of 0.72, 0.5 and 0.4 respectively.

The wall thickness for the CS pipe shall be initially calculated by following expression.

As per ASME B31.8 clause 841.1.1, the formula for the wall thickness calculation of gas pipeline

is:

t

min

= [P

D

D / (2FSET)] + A

where,

(9)

S

= Specified Minimum Yield Strength (SMYS)

t

min

= Calculated Minimum Wall thickness

D

= Outside diameter of pipe

F

= Design factor (Ref Table 841.1.6-1 of ASME B31.8)

E

= Longitudinal joint factor (Ref Table 841.1.7-1 of ASME B31.8)

T

= Temperature derating factor (Ref Table 841.1.8-1 of ASME B31.8)

A

= Corrosion Allowance

The Thickness calculated from above is then checked for acceptability of the ratio of diameter to

thickness for final thickness selection and it should not exceed 96.

6.2. Pipe Thickness Check for Stress Value

The stresses are calculated for the pipe wall thickness as per equations given below:

a) Hoop Stress

Hoop stress, S

H

= P

D

D / 2t

(Clause 805.2.3 of ASME B31.8)

b) Longitudinal Stress



Longitudinal stress due to pressure:

For restrained pipe:

S

P

= 0.3 S

H

(Clause 833.2 (a) of ASME B31.8)

For unrestrained pipe:

S

P

= 0.5 S

H

(Clause 833.2 (b) of ASME B31.8)



Longitudinal stress due to thermal expansion in restrained pipe (thermal stress):

S

T

= E



(T

1

– T

2

) (Clause 833.2 (c) of ASME B31.8)



Longitudinal stress due to bending:

S

B

= M / Z (Clause 833.2 (d) of ASME B31.8)



Longitudinal stress due to axial loading other than thermal expansion and pressure:

S

X

= R / A (Clause 833.2 (f) of ASME B31.8)

(10)

For restrained pipe:

S

L

= S

P

+ S

T

+ S

B

+ S

X

(Clause 833.3 (a) of ASME B31.8)

For unrestrained pipe: S

L

= S

P

+ S

B

+ S

X

(Clause 833.6 (a) of ASME B31.8)

Where:

E

=

Modulus of elasticity at ambient temperature



=

Thermal expansion coefficient

T

1

=

pipe temperature at the time of installation, tie-in or burial

T

2

=

Warmest operating temperature

M =

Bending moment across the pipe cross-section

Z =

Pipe section modulus

R =

External force axial component

A =

Pipe metal cross-sectional area

c) Combined / Equivalent Stress

The combined/equivalent stress of the restrained pipe is evaluated using the calculation in

either (1) or (2) below (Ref clause 833.4(a) of ASME B31.8):

(1) S

E1

= S

H

– S

L

(2) S

E2

= [S

H2

+ S

L2

- S

H

S

L

] ½

d) Criteria

The calculated stress needs to fulfill the criteria given below:

The net longitudinal stress, S

L

:

For restrained pipe (Ref clause 833.3(b) of ASME B31.8):

S

L

≤ 0.9 SMYS x T

For unrestrained pipe (Ref clause 833.6(b) of ASME B31.8): S

L

≤ 0.75 SMYS x T

The combined / equivalent stress for restrained pipe (Ref clause 833.4 of ASME B31.8),

S

E1

and S

E2

≤ k x SMYS x T, where k ≤ 0.9 for load of long durations

(11)

6.3. Minimum Elastic Bending Radius

The route and profile of any fully restrained section of pipelines should be controlled to ensure

that the elastic bend limit or minimum allowable elastic bending radius is not exceeded.

The minimum elastic bending radius is determined as explained below.

1. The net longitudinal stress S

L

in section 6.2(b) shall be calculated in terms of S

B

2. By substituting the calculated S

L

in terms of S

B

into combined / equivalent stress equation

6.2 (c), S

E

is derived in terms of S

B

.

3. Based on criteria mentioned in section 6.2 (d), combined / equivalent stress shall be less

than 90% of SMYS for k = 0.9 and T = 1. Hence, maximum allowable margin for bending

stress can be derived by substituting the values of combined / equivalent stress S

E

in terms

of S

B

into the criteria.

By adjusting the Minimum Elastic Bending Radius (R) in below equation, we can ensure that

Bending Stress is within the allowable margin to meet the above criteria.

R = ED / 2S

B

For pipelines assuming a natural curvature that incurs a permanent elastic bending stress, the

minimum bending radius as per the calculation specified in Attachment-1 for respective wall

thickness shall be followed.

6.4. Bend Thinning Requirements

Wall thickness check, also takes into account the bend thinning requirements in accordance

with Clause 6.2.2.3 of PD 8010-1:2004. This is in the case of subjecting the pipe to field

bending or cold bending having a minimum bend radius of 40D and Factory hot bends with a

bend radius of 5D.

The wall thinning as a percentage is given by following empirical formula.

Wall thinning % = 50 / (n +1)

Where n = inner bend radius divided by pipe diameter.

By equating the calculated pipe thickness and bend thickness after bending, the calculated

thickness for design pressure = (1- thinning %) x pipe thickness before bend.

Pipe thickness before bending = (Calculated thickness for design pressure) / (1 – Thinning %)

The bend wall thinning allowance considered for the project shall be verified / confirmed by Hot

Bends Supplier.

(12)

7. DESCRIPTION / METHODOLOGY - UPHEAVAL BUCKLING CALCULATION

7.1. General

The simplified method presented in OTC Paper 6335 by A.C. Palmer, C. P. Ellinas, D.M.

Richards and J. Guijt (presented at 22nd Annual OTC in Houston, Texas, May 7-10, 1990) is

used to check that the selected depth of cover for pipeline is adequate to prevent upheaval

buckling.

The calculation is done for both new and corroded condition of pipes.

7.2. Methodology

The required downward force to prevent upheaval buckling of pipe is a function of pipe flexural

rigidity (EI) and the axial compressive force due to pressure and temperature load. The equation

12 of OTC paper 6335 gives the required download for stability in the operating condition:

W = [1.16 – 4.76 (EI W

o

/ δ)

0.5

/ P



P (δW

o

/ EI)

0.5

…………. (1)

Where,

W

=

Required download force to prevent upheaval buckling

E

=

Young’s modulus of steel

I

=

Section modulus for pipe

δ

=

Allowable Imperfection height

P

=

Effective axial force in operation

W

o

=

Weight of pipe + Weight of content + Weight of corrosion coating

per unit length

The vertical download force that resists uplift of pipeline is related to the profile imperfection and

therefore a term imperfection height is appearing in the above formula. The soil resistance also

changes with increase in imperfection height. Upheaval buckling check has been carried out for

various imperfection heights from 0.1 to 0.5m.

7.3. Calculation for Axial Force (P)

The axial force on buried pipeline section will include following forces:

a) Axial tensile stress due to hoop stress = ٧Sh

Where,

٧ =

Poissons ratio i.e. 0.3 for steel pipe

(13)

b) Axial Compressive stress due to internal pressure = 0.3 x Sh

c) Axial Compressive force due to temperature change = Eα(T2-T1)

Where,

E

=

Modulus of elasticity

α

=

Thermal expansion coefficient

T

2

=

Design temperature for underground section

T

1

=

Installation temperature

The Axial Force,

P = P

D

Ai + A{E α (T2-T1) - ٧Sh } …………. (2)

Where,

Ai

=

Area corresponding to internal cross-section of Pipe

A

=

Cross-Section area of Pipe

P

D

=

Design pressure

Axial force calculated above is considering fully restrained condition of pipeline (more

conservative scenario)

The soil above the buried pipeline will provide an uplift resistance, (as per OTC paper Eq 13),

Q = HD Ƴ[1+f H / D] …………. (3)

Where,

Q

=

Uplift Soil resistance per unit length

H

=

pipe cover

D

=

Pipe outside diameter

Ƴ

=

Soil density

f

=

Uplift

coefficient

(0.1

for

loose

material

&

0.5 for dense material)

To prevent the upheaval buckling of pipeline, |W| < |Wo + Q|

7.4. Imperfection Length

Maximum downward force per unit length required to stabilize the pipeline at the crest of the

profile imperfection (as per OTC paper Eq 4 )

(14)

where, L

imp

= Imperfection Length

L

imp

shall be calculated by solving the quadratic equation as follows

(π / L

imp

)

4

– [P / 4EI] (π / L

imp

)

2

+ [ W / 8δEI ] = 0

8. DESCRIPTION / METHODOLOGY – ROAD CROSSING CALCULATION

8.1. General

The purpose of this calculation is to ensure satisfactory and optimal design in compliance with

criteria (circumference stress due to internal pressure as per Barlow formula, effective stress

and fatigue) defined in API RP 1102, and to determine whether wall thicknesses heavier than

the selected wall thickness would be required at road crossing.

The following wheel loadings were taken into account in determining the stresses imposed on

pipeline.



Asphalt Road/ Highway /Track crossings: 112kN per wheel at 900mm centers with

maximum of four (4) wheels per axle. Contact area per API RP 1102 is 0.093 square

meters, giving surface pressure = 1204 kN/m

2

.



Rig crossings: 2200 kN on a single axle (2 wheel set) and the maximum single axle wheel

load is 1100kN. The contact area, over which the wheel load is applied, shall be taken as

0.403 square meters.

8.2. Methodology

The methodology for track/asphalt road/rig crossing calculations (as mentioned in API 1102) is

described briefly in the following steps:

a. Begin with the wall thickness (calculated with design factor 0.5 for Class 1 and 3 and design

factor 0.4 for Class 4) for pipeline of given diameter approaching the crossing. Determine

the pipe, soil, construction, and operational characteristics.

b. Use the Barlow formula to calculate the circumferential stress due to internal pressure, S

hi

(Barlow). Check S

hi

against the maximum allowable value.

c. Calculate the circumferential stress due to earth load, S

He

.

d. Check the critical axle configuration as per figure A-1 Annex. A of API 1102.

e. Calculate the external live load, w, and determine the appropriate impact factor, Fi.

(15)

f.

Calculate the cyclic circumferential stress, ΔS

H

, and the cyclic longitudinal stress, ΔS

L

, due

to live load.

g. Calculate the circumferential stress due to internal pressure, S

Hi

h. Check effective stress, S

eff

, as follows:

1. Calculate the principal stresses, S

1

in the circumferential direction, S

2

in longitudinal

direction, and S

3

in the radial direction.

2. Calculate the effective stress, S

eff

.

3. Check by comparing S

eff

against the allowable stress, SMYS x F.

i.

Check weld for fatigue as follows:

1. Check with weld fatigue by comparing ΔS

L

against the girth weld fatigue limit, S

FG

x F.

2. Check longitudinal weld fatigue by comparing, ΔS

H

against the longitudinal weld fatigue

limit, S

FL

x F.

where,



Circumferential stress due to internal pressure,

S

hi

(Barlow) = P

D

D ⁄ 2t

w

(refer section 4.8.1.1 of API 1102)



Circumferential stress due to earth load,

S

He

= K

He

B

e

E

e

γ D

(refer section 4.7.2.1 of API 1102)

K

He

is the stiffness factor for circumferential stress from earth load.

B

e

is the burial factor for earth load.

E

e

is the excavation factor for earth load.

γ is the soil unit weight.



Surface pressure due to Live load,

w = P ⁄ A

P

(refer section 4.7.2.2 of API 1102)

P may be Design single wheel load P

S

or Design tandem wheel load P

T

A

P

is the contact area over which the wheel load is applied

(16)

ΔS

Hh

= K

Hh

G

Hh

RLF

i

w

(refer section 4.7.2.2.4.1 of API 1102)

K

Hh

is the highway stiffness factor for cyclic circumferential stress.

G

Hh

is the highway geometry factor for cyclic circumferential stress.

R is the highway Pavement type factor.

L is the highway axle configuration factor.

Fi is the impact factor.

w is the applied design surface pressure.



Cyclic longitudinal stress due to highway vehicular load,

ΔS

Lh

= K

Lh

G

Lh

RLF

i

w

(refer section 4.7.2.2.4.2 of API 1102)

K

Lh

is the highway stiffness factor for cyclic longitudinal stress.

G

Lh

is the highway geometry factor for cyclic longitudinal stress.

R is the highway pavement type factor.

L is the highway axle configuration factor.

F

i

is the impact factor.

w is the applied design surface pressure.



Circumferential stress due to internal pressure,

S

Hi

= P

D

(D– t

w

) ⁄ 2t

w

(refer section 4.7.3 of API 1102)



Maximum circumferential stress,

S

1

= S

He

+ ΔS

H

+ S

Hi

(refer section 4.8.1.2 of API 1102)



Maximum longitudinal stress,

S

2

= ΔS

L

– E

s

α

T

(T

2

– T

1

) + ν

s

(S

He

+ S

Hi

)

(refer section 4.8.1.2 of API 1102)



Maximum radial stress,

S

3

= –p = –P

D

(Design Pressure)

(refer section 4.8.1.2 of API 1102)



Total effective stress,

(17)

9. CALCULATION RESULT / SUMMARY

For calculation details, refer to Attachments - 1, 2, 3, 4 and 5.

Based on the calculation results, the selected wall thicknesses for pipelines as listed below are

found adequate for the anticipated design pressures and temperatures, combined / equivalent

stresses, upheaval buckling and withstand the expected traffic / wheel loadings at Track,

Asphalt Road/ Highway and Rig crossing at the specified depth.

9.1. Result for Wall Thickness Calculation

Wall thickness of Pipeline

52” Sales Gas

Pipeline, API 5L X65

42” Sales Gas

Pipeline, API 5L X65

16” Sales Gas

Pipeline, API 5L X65

Location

Class

Calculated

WT (mm)

Selected

WT (mm)

Calculated

WT (mm)

Selected

WT (mm)

Calculated

WT (mm)

Selected

WT (mm)

4

24.8

25.2 NA

NA

3

20.1

20.5

16.5

16.9

7.2

14.7

1

14.4

14.7 NA

NA

Wall thickness check for 40D field/cold bends

52” Sales Gas

Pipeline, API 5L X65

42” Sales Gas

Pipeline, API 5L X65

16” Sales Gas

Pipeline, API 5L X65

Location

Class

Calculated

WT (mm)

Selected

WT (mm)

Calculated

WT (mm)

Selected

WT (mm)

Calculated

WT (mm)

Selected

WT (mm)

4

25.1

25.2 NA

NA

3

20.4

20.5

16.8

16.9

7.3

14.7

1

14.6

14.7 NA

NA

(18)

Wall thickness of Mother pipes for 5D Factory Hot bends

52” Sales Gas

Pipeline, API 5L X65

42” Sales Gas

Pipeline, API 5L X65

16” Sales Gas

Pipeline, API 5L X65

Location

Class

Calculated

WT (mm)

Selected

WT (mm)

Calculated

WT (mm)

Selected

WT (mm)

Calculated

WT (mm)

Selected

WT (mm)

4

27.3

28.0 NA

NA

3

22.1

25.2

18.2

18.8

8.0

14.7

1

15.9

20.5 NA

NA

Check for D/t ratio

Description

Class - 4 Class -3 Class -1 Class-3 Class-3

Pipeline Diameter , inch

52

42

16 Pipeline Outer Diameter D, mm

1320.8

1066.8

406.4 Selected Wall Thickness t, mm

25.2

20.5

14.7

16.9

14.7 D/t Ratio

52

64

90

63

28

(19)

Result for Stresses and minimum elastic bending radius (Non-Corroded condition)

52” (Location

Class 4)

52”

(Location

Class 3)

52”

(Location

Class 1)

42”

(Location

Class 3)

16”

(Location

Class 3)

Selected Wall

Thickness (mm)

25.2

20.5

14.7

16.9

14.7 Combined /

Equivalent

Stress of

unrestrained

section in MPa

(% of SMYS)

144.1(32.02%)

177.2 (39.37%)

247.1 (54.91%)

173.6 (38.57%)

76 (16.89%)

Combined /

Equivalent

Stress of

Restrained

section in MPa

(% of SMYS)

238.6 (53.02%)

265.3 (58.95%)

321.8 (71.51%)

262.4 (58.31%)

183.6 (40.8%)

Margin for

Bending Stress

in MPa (% of

SMYS)

166.6 (37.02%)

139.9 (31.08%)

83.4 (18.53)

142.8 (31.73)

221.6 (49.24)

Min. Elastic Bend

(20)

Result for Stresses and Minimum Elastic Bend Radius (Corroded Condition)

52” (Location

Class 4)

52”

(Location

Class 3)

52”

(Location

Class 1)

42”

(Location

Class 3)

16”

(Location

Class 3)

Selected Wall

Thickness (mm)

25.2

20.5

14.7

16.9

14.7 Corroded wall

thickness (mm)

23.7

19.0

13.2

15.4

13.2 Combined /

Equivalent

Stress of

unrestrained

section in MPa

(% of SMYS)

153.2 (34.04%)

191.1 (42.46%)

275.1 (61.13%)

190.5 (42.33%)

84.7 (18.82%)

Combined /

Equivalent

Stress of

Restrained

section in MPa

(% of SMYS)

246 (54.66%)

276.6 (61.46%)

344.5 (76.55%)

276.1 (61.35%)

190.5 (42.33%)

Margin for

Bending Stress

in MPa (% of

SMYS)

159.2(35.37%)

128.6 (28.57%)

60.7 (13.48%)

129.1 (28.68%)

214.7 (47.71%)

Min. Elastic Bend

Radius (m)

832 1031

2184

829

190 Minimum elastic bending radius to be considered for Construction shall be as per the value

calculated in corroded condition.

(21)

9.2. Result for Upheaval Buckling Calculation

Calculation for Non-Corroded & Corroded Conditions

Result

Size

Location

Class

Wall Thickness

(mm)

Depth of Cover

(m)

52” SALES GAS

PIPELINE, API 5L X65

4

25.2

1.5 OK

3

20.5

1.0 OK

1

14.7

1.0 OK

42” SALES GAS

PIPELINE, API 5L X65

3

16.9

1.0 OK

16” SALES GAS

PIPELINE, API 5L X65

3

14.7

1.0 OK

(22)

9.3. Result for Crossing Calculation

Crossing

52” SALES GAS

PIPELINE, API 5L

X65

42” SALES GAS

PIPELINE, API 5L

X65

16” SALES GAS

PIPELINE, API 5L X65

Wall Thick.

(mm)

Burial

Depth

(m)

Wall

Thick.

(mm)

Burial

Depth

(m)

Wall

Thick.

(mm)

Burial

Depth (m)

Location Class = 4

Track Crossing

25.2

2 NA

NA

Asphalt Road

Crossing/

Highway

Crossing

25.2 (Note-1)

2 NA

NA

Rig Crossing

25.2

2 NA

NA

Location Class = 3

Track Crossing

20.5

1.5

16.9

1.5

14.7

1.5 Asphalt Road

Crossing/

Highway

Crossing

20.5 (Note-1)

2

16.9 (Note-1)

2 NA

NA

Rig Crossing

20.5

2

16.9

2 NA

NA

Location Class = 1

Track Crossing

20.5

1.5 N/A

N/A

NA

Asphalt Road

Crossing/

Highway

Crossing

20.5 (Note-1)

2 N/A

N/A

NA

Rig Crossing

20.5

2 N/A

N/A

NA

Result

OK

(23)

9.4. Result for Anchor Load, Active length, free end expansion and Buoyancy

Non Corroded Condition

52”

(Location

Class 4)

52”

(Location

Class 3)

52”

(Location

Class 1)

42”

(Location

Class 3)

16”

(Location

Class 3)

Selected Wall

Thickness (mm)

25.2

20.5

14.7

16.9

14.7 Free End

Expansion

(Non-compacted) (mm)

495 (Note-1)

440 (Note-1)

N/A

366 (Note-1)

259 (Note-1)

Free End

Expansion

(Compacted) (mm)

445 (Note-1)

395 (Note-1)

N/A

328 (Note-1)

232 (Note-1)

Anchor Load in

Tonne

1616

(Note 3)

1384

(Note 3)

N/A

916 (Note 3)

256 (Note 3)

Active Length

(Non-compacted)

(m)

753.86

659.5 N/A

549.8

407.78 Active Length

(Compacted) (m)

678.59

592.41 N/A

493

365.23 Factor of Safety

against floatation

0.573 (Note-2)

0.468 (Note-2)

0.337 (Note-2)

0.477 (Note-2)

1.068 (Note-2)

(24)

Corroded Condition

52”

(Location

Class 4)

52”

(Location

Class 3)

52”

(Location

Class 1)

42”

(Location

Class 3)

16”

(Location

Class 3)

Selected Wall

Thickness (mm)

25.2

20.5

14.7

16.9

14.7 Corroded wall

thickness (mm)

23.7

19

13.2

15.4

13.2 Free End

Expansion

(Compacted)

(mm)

429 (Note-1)

379 (Note-1)

N/A

311 (Note-1)

214 (Note-1)

Anchor Load

(tonne)

1542

(Note 3)

1310

(Note 3)

N/A

857 (Note 3)

234 (Note 3)

Active Length

(Compacted)

(m)

651.51

564 N/A

463.65

336 Factor of Safety

against

floatation

0.540 (Note-2)

0.434 (Note-2)

0.303 (Note-2)

0.436 (Note-2)

0.963 (Note-2)

Anchor load shall be considered based on non corroded condition. However, the value obtained

from approved stress analysis shall be used for design of anchor block.

Notes:

1) Values less than 25mm at A/G U/G transition point can be accepted and these can be

accommodated in A/G portion of the pipeline with sliding supports in the pig trap. Values

greater than 25mm are not acceptable and should be reduced by anchoring in the U/G

section of the pipeline as per the stress analysis report.

2) It is not anticipated that construction will be carried out in ground water because where

ground water is encountered; the pipeline will be installed on filled ground above the water

table in accordance with the typical drawings for Sabkha Construction. However,

Anti-buoyancy calculation is carried out to check pipeline stability in case pipeline installation

inside the water table is approved by COMPANY in unavoidable circumstances. The

(25)

calculation result FOS value less than 1.0 indicates that the pipeline is buoyant. A FOS

value greater than 1.1 is recommended to prevent pipe floatation against negative buoyancy

in case pipeline is laid inside water table.

(26)

ATTACHMENT-1A & 1B: WALL THICKNESS CALCULATIONS (CORRODED & NEW CONDITION)

(No. of Sheets – 10+5)

(27)

ATTACHMENT-2: UPHEAVAL BUCKLING CALCULATION

(No. of Sheets – 10)

(28)

ATTACHMENT-3: CROSSING CALCULATIONS

(No. of Sheets – 13)

(29)

ATTACHMENT-4: PIPELINE BUOYANCY CALCULATION

(No. of Sheets – 5)

(30)

ATTACHMENT-5: ANCHOR LOAD, ACTIVE LENGTH & FREE EXPANSION CALCULATION

(No. of Sheets – 15)

(31)

13 Aboveground Design Temp. T2 100

o

C 212.0 oF

14 Underground Design Temp. T3 65

o_C

149.0 oF

15 Weld joint factor E 1

16 Temperature Derating Factor T 1

17 Max. factor for load of long durations k 0.9

18

19 A. WALL THICKNESS

20 Grade X65

21 SMYS of Line Pipe S 65300 psi 450 MPa

22 Wall Thickness Calculated tmin 24.8 mm 0.976 inch

23 tmin = PD / (2SFET) + A

24 Selected wall thickness t 25.2 mm 0.992 inch

25 D/t Check ( Should be < 96) 52

26

27 B. COMBINED / EQUIVALENT STRESS CHECK FOR NEW PIPE CONDITION

28 Wall thickness (t) 25.2 mm 0.992 inch

29 Hoop Stress = SH = PD/2t 166.4 MPa 24136 psi

30

31 B.1 Restrained Pipe (Underground)

32 Thermal Stress = ST = α (T1 - T3) E -122.1 MPa -17711 psi

33 Longitudinal Stress due to pressure = SP = 0.3 SH 49.9 MPa 7241 psi

34

35 Longitudinal Stress, SL

36 SL = SP + ST + SB + SX ≤ 0.9 x SMYS x T = 406 MPa 58770 psi

37

38 Without considering SB (Bending stress) and SX (Axial stress due to external loading):

39 SL = SP + ST -72.2 MPa -10471 psi

40 Longitudinal Stress check : SL ≤ 0.9 x SMYSxT hence OK 41 42 Combined Stress, SE 43 SE1 = | SH - SL | SE1 238.6 MPa 34606 psi 44 SE2 = [ SH 2 + SL 2 - SH SL ] 1/2 _S E2 211.9 MPa 30739 psi

45 SE = Max (SE1, SE2) ≤ k x SMYS xT = 406 MPa SE 238.6 MPa 34606 psi

46 Combined/Equivalent Stress check : SE≤ 0.9 x SMYSxT hence OK 47

48 B.2 Unrestrained Pipe (Aboveground)

50

52 SL = SP +SB + SX ≤ 0.75 x SMYS x T = 338 MPa 48975 psi

54 SL = SP 83.2 MPa 12068 psi

55 Longitudinal Stress check : SL ≤ 0.75 x SMYSxT hence OK 56

57 Combined Stress, SE

58 SE1 = | SH - SL | SE1 83.2 MPa 12068 psi

59 SE2 = [ SH2 + SL2 - SH SL ]1/2 SE2 144.1 MPa 20902 psi

63 C. MINIMUM BENDING RADIUS

64 Minimum bending radius for underground section is calculated from margin for elastic bending,

65 = (0.9 x SMYS x T) - SE 166.6 MPa 24163 psi

66 R (Minimum Bend Radius) = E D / (2 |Sb|) 796 m

67 68 69 70 71 72 73 74 75 Page 1 of 10

(32)

11 Corrosion Allowance

A

1.5 mm

12

13 A. CHECK ON THINNING FOR FACTORY HOT BENDS: BEND RADIUS = 5 D

14 Calculated required thk, t

24.8 mm

15 t = P x D / (2x Sx Fx E x T) + A

16 Selected Mainline Wall Thickness

25.2 mm

17 n, Inner Bend radius divided by diameter

4.5

18 9.1 %

19 Pipe Thk. Before bending (cal thk)/(1-thinning %)

27.3 mm

20 Selected thickness for bend making

28.0 mm

21 Adequacy Check (Pipe thk before bending < Available thk)

OK

22

23

24 B. CHECK ON THINNING FOR FIELD OR COLD BENDS: BEND RADIUS = 40 D

25 Inner bend radius divided by diameter, (n)

39.5

26

1.23 %

27 Pipe thk. before bending = cal thk/(1-thinning %)

25.1 mm

28 Available thickness for bending (= Selected thk)

25.2 mm

29 Adequacy Check (Pipe thk before bending < Available thk)

OK

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55 As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

(33)

o

C 212.0 oF

o_C

149.0 oF

17 Max. factor for load of long durations k 0.9 18

20 Grade X65

26

30

34

37

39 SL = SP + ST -60.7 MPa -8811 psi

50

54 SL = SP 102.3 MPa 14835 psi

58 SE1 = | SH - SL | SE1 102.3 MPa 14835 psi

67 68 69 70 71 72 73 74 75 Page 3 of 10

(34)

11 Corrosion Allowance

A

1.5 mm

12

13 A. CHECK ON THINNING FOR FACTORY HOT BENDS: BEND RADIUS = 5 D

14 Calculated required thk, t

20.1 mm

15 t = P x D / (2x Sx Fx E x T) + A

16 Selected Mainline Wall Thickness

20.5 mm

17 n, Inner Bend radius divided by diameter

4.5

18 9.1 %

19 Pipe Thk. Before bending (cal thk)/(1-thinning %)

22.1 mm

20 Selected thickness for bend making

25.2 mm

21 Adequacy Check (Pipe thk before bending < Available thk)

OK

22

23

24 B. CHECK ON THINNING FOR FIELD OR COLD BENDS: BEND RADIUS = 40 D

25 Inner bend radius divided by diameter, (n)

39.5

26

1.23 %

27 Pipe thk. before bending = cal thk/(1-thinning %)

20.4 mm

28 Available thickness for bending (= Selected thk)

20.5 mm

29 Adequacy Check (Pipe thk before bending < Available thk)

OK

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55 As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

(35)

o

C 212.0 oF

o_C

149.0 oF

18

20 Grade X65

26

30

34

37

39 SL = SP + ST -36.5 MPa -5299 psi

40 Combined/Equivalent Stress check : SL ≤ 0.9 x SMYSxT hence OK 41 42 Combined Stress, SE 43 SE1 = | SH - SL | SE1 321.8 MPa 46674 psi 44 SE2 = [ SH 2 + SL 2 - SH SL ] 1/2 _S E2 305.2 MPa 44264 psi

46 Combined Stress check : SE≤ 0.9 x SMYSxT hence OK 47

50

54 SL = SP 142.6 MPa 20688 psi

58 SE1 = | SH - SL | SE1 142.6 MPa 20688 psi

67 68 69 70 71 72 73 74 75 Page 5 of 10

(36)

11 Corrosion Allowance

A

1.5 mm

12

13 A. CHECK ON THINNING FOR FACTORY HOT BENDS: BEND RADIUS = 5 D

14 Calculated required thk, t

14.4 mm

15 t = P x D / (2x Sx Fx E x T) + A

16 Selected Mainline Wall Thickness

14.7 mm

17 n, Inner Bend radius divided by diameter

4.5

18 9.1 %

19 Pipe Thk. Before bending (cal thk)/(1-thinning %)

15.9 mm

20 Selected thickness for bend making

20.5 mm

21 Adequacy Check (Pipe thk before bending < Available thk)

OK

22

23

24 B. CHECK ON THINNING FOR FIELD OR COLD BENDS: BEND RADIUS = 40 D

25 Inner bend radius divided by diameter, (n)

39.5

26

1.23 %

27 Pipe thk. before bending = cal thk/(1-thinning %)

14.6 mm

28 Available thickness for bending (= Selected thk)

14.7 mm

29 Adequacy Check (Pipe thk before bending < Available thk)

OK

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55 As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

(37)

o

C 212.0 oF

o_C

149.0 oF

18

20 Grade X65

26

30

34

37

39 SL = SP + ST -62.0 MPa -8991 psi

50

54 SL = SP 100.2 MPa 14534 psi

58 SE1 = | SH - SL | SE1 100.2 MPa 14534 psi

67 68 69 70 71 72 73 74 75 Page 7 of 10

(38)

11 Corrosion Allowance

A

1.5 mm

12

13 A. CHECK ON THINNING FOR FACTORY HOT BENDS: BEND RADIUS = 5 D

14 Calculated required thk, t

16.5 mm

15 t = P x D / (2x Sx Fx E x T) + A

16 Selected Mainline Wall Thickness

16.9 mm

17 n, Inner Bend radius divided by diameter

4.5

18 9.1 %

19 Pipe Thk. Before bending (cal thk)/(1-thinning %)

18.2 mm

20 Selected thickness for bend making

18.8 mm

21 Adequacy Check (Pipe thk before bending < Available thk)

OK

22

23

24 B. CHECK ON THINNING FOR FIELD OR COLD BENDS: BEND RADIUS = 40 D

25 Inner bend radius divided by diameter, (n)

39.5

26

1.23 %

27 Pipe thk. before bending = cal thk/(1-thinning %)

16.8 mm

28 Available thickness for bending (= Selected thk)

16.9 mm

29 Adequacy Check (Pipe thk before bending < Available thk)

OK

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55 As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

(39)

o

C 212.0 oF

o_C

149.0 oF

18

20 Grade X65

26

30

34

37

39 SL = SP + ST -95.8 MPa -13892 psi

50

54 SL = SP 43.9 MPa 6365 psi

58 SE1 = | SH - SL | SE1 43.9 MPa 6365 psi

67 68 69 70 71 72 73 74 75 Page 9 of 10

(40)

11 Corrosion Allowance

A

1.5 mm

12

13 A. CHECK ON THINNING FOR FACTORY HOT BENDS: BEND RADIUS = 5 D

14 Calculated required thk, t

7.2 mm

15 t = P x D / (2x Sx Fx E x T) + A

16 Selected Mainline Wall Thickness

14.7 mm

17 n, Inner Bend radius divided by diameter

4.5

18 9.1 %

19 Pipe Thk. Before bending (cal thk)/(1-thinning %)

8.0 mm

20 Selected thickness for bend making

14.7 mm

21 Adequacy Check (Pipe thk before bending < Available thk)

OK

22

23

24 B. CHECK ON THINNING FOR FIELD OR COLD BENDS: BEND RADIUS = 40 D

25 Inner bend radius divided by diameter, (n)

39.5

26

1.23 %

27 Pipe thk. before bending = cal thk/(1-thinning %)

7.3 mm

28 Available thickness for bending (= Selected thk)

14.7 mm

29 Adequacy Check (Pipe thk before bending < Available thk)

OK

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55 As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

As per Cl 6.2.2.3 of PD 8010-1:2004,% of wall thinning

(50)/(n+1)

(41)

o

C 212.0 oF

o_C

149.0 oF

18

20 Grade X65

26

27 B. COMBINED /EQUIVALENT STRESS CHECK FOR CORRODED PIPE CONDITION

30

34

37

39 SL = SP + ST -69.0 MPa -10012 psi

50

54 SL = SP 88.5 MPa 12832 psi

58 SE1 = | SH - SL | SE1 88.5 MPa 12832 psi

67 68 69 70 71 72 73 74 75 Page 1 of 5

(42)

o

C 212.0 oF

o_C

149.0 oF

18

20 Grade X65

26

27 B. COMBINED /EQUIVALENT STRESS CHECK FOR CORRODED PIPE CONDITION

30

34

37

39 SL = SP + ST -55.9 MPa -8108 psi

50

54 SL = SP 110.4 MPa 16006 psi

58 SE1 = | SH - SL | SE1 110.4 MPa 16006 psi

67 68 69 70 71 72 73 74 75 Page 2 of 5

Engineering Calculation Pipeline

REVISION RECORD:

Revision

No.

Reason for revision

Date

0

Issued for Construction

19.12.2012

C

Re-Issued for Approval incorporating Client comments

09.12.2012

B

Issued for Approval incorporating Client comments

06.11.2012

A

Issued for Client Review

16.10.2012

TABLE OF CONTENTS

1.

INTRODUCTION ...

5

1.1.

Background ...

5

1.2.

Project Description ...

5

2.

DEFINITIONS ...

5

3.

SCOPE ...

6

4.

REFERENCE CODES, STANDARDS AND SPECIFICATIONS ...

6

4.1.

General ...

6

4.2.

International Codes and Standards ...

6

4.3.

Project Documents ...

6

5.

PIPELINE DESIGN DATA ...

7

6.

DESCRIPTION / METHODOLOGY - WALL THICKNESS CALCULATION...

8

6.1.

General ...

8

6.2.

Pipe Thickness Check for Stress Value ...

9

6.3.

Minimum Elastic Bending Radius ...

11

6.4.

Bend Thinning Requirements ...

11

7.

DESCRIPTION / METHODOLOGY - UPHEAVAL BUCKLING CALCULATION

12

7.1.

General ...

12

7.2.

Methodology ...

12

7.3.

Calculation for Axial Force (P) ...

12

7.4.

Imperfection Length ...

13

8.

₅

₅

₆

₆

₇

₈

₁₂

₁₇

₂₆

₂₇

₂₉